TextLCD.cpp

00001 /* mbed TextLCD Library, for a 4-bit LCD based on HD44780
00002  * Copyright (c) 2007-2010, sford, http://mbed.org
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00020  * THE SOFTWARE.
00021  */
00022 
00023 #include "TextLCD.h"
00024 #include "mbed.h"
00025 
00026 TextLCD::TextLCD(PinName rs, PinName e, PinName d0, PinName d1,
00027                  PinName d2, PinName d3, LCDType type) : _rs(rs),
00028         _e(e), _d(d0, d1, d2, d3),
00029         _type(type) {
00030 
00031     _e  = 0;
00032     _rs = 0;            // command mode
00033     
00034     wait(0.050);        // Wait 15ms to ensure powered up
00035 
00036     // send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus)
00037     for (int i=0; i<3; i++)  {
00038         writeByte(0x30);
00039         wait(0.002);  // this command takes 1.64ms, so wait for it
00040     }
00041     writeByte(0x2);
00042         wait(0.002); 
00043     writeCommand(0x29);
00044     wait(0.001f);
00045     writeCommand(0x14);
00046     wait(0.001f);
00047     writeCommand(0x55);
00048     wait(0.001f);
00049     writeCommand(0x6D);
00050     wait(0.001f);
00051     writeCommand(0x78);
00052     wait(0.001f);
00053     writeCommand(0x28);
00054     wait(0.001f);
00055     writeCommand(0x0C);
00056     wait(0.001f);
00057     writeCommand(0x01);
00058     wait_ms(2);
00059     writeCommand(0x06);
00060     wait(0.001f);
00061 }
00062 
00063 void TextLCD::character(int column, int row, int c) {
00064     int a = address(column, row);
00065     writeCommand(a);
00066     writeData(c);
00067 }
00068 
00069 void TextLCD::cls() {
00070     writeCommand(0x01); // cls, and set cursor to 0
00071     wait(0.00164f);     // This command takes 1.64 ms
00072     locate(0, 0);
00073 }
00074 
00075 void TextLCD::locate(int column, int row) {
00076     _column = column;
00077     _row = row;
00078 }
00079 
00080 int TextLCD::_putc(int value) {
00081     if (value == '\n') {
00082         _column = 0;
00083         _row++;
00084         if (_row >= rows()) {
00085             _row = 0;
00086         }
00087     } else {
00088         character(_column, _row, value);
00089         _column++;
00090         if (_column >= columns()) {
00091             _column = 0;
00092             _row++;
00093             if (_row >= rows()) {
00094                 _row = 0;
00095             }
00096         }
00097     }
00098     return value;
00099 }
00100 
00101 int TextLCD::_getc() {
00102     return -1;
00103 }
00104 
00105 void TextLCD::writeByte(int value) {
00106     _d = value >> 4;
00107     wait(0.000040f); // most instructions take 40us
00108     _e = 0;
00109     wait(0.000040f);
00110     _e = 1;
00111     _d = value >> 0;
00112     wait(0.000040f);
00113     _e = 0;
00114     wait(0.000040f);  // most instructions take 40us
00115     _e = 1;
00116 }
00117 
00118 void TextLCD::writeCommand(int command) {
00119     _rs = 0;
00120     writeByte(command);
00121 }
00122 
00123 void TextLCD::writeData(int data) {
00124     _rs = 1;
00125     writeByte(data);
00126 }
00127 
00128 int TextLCD::address(int column, int row) {
00129     switch (_type) {
00130         case LCD20x4:
00131             switch (row) {
00132                 case 0:
00133                     return 0x80 + column;
00134                 case 1:
00135                     return 0xc0 + column;
00136                 case 2:
00137                     return 0x94 + column;
00138                 case 3:
00139                     return 0xd4 + column;
00140             }
00141         case LCD16x2B:
00142             return 0x80 + (row * 40) + column;
00143         case LCD16x2:
00144         case LCD20x2:
00145         default:
00146             return 0x80 + (row * 0x40) + column;
00147     }
00148 }
00149 
00150 int TextLCD::columns() {
00151     switch (_type) {
00152         case LCD20x4:
00153         case LCD20x2:
00154             return 20;
00155         case LCD16x2:
00156         case LCD16x2B:
00157         default:
00158             return 16;
00159     }
00160 }
00161 
00162 int TextLCD::rows() {
00163     switch (_type) {
00164         case LCD20x4:
00165             return 4;
00166         case LCD16x2:
00167         case LCD16x2B:
00168         case LCD20x2:
00169         default:
00170             return 2;
00171     }
00172 }